Collaborative Research: Controlling Microstructure in Resilin-based Hydrogels: Linking Microscale Mechanical Properties to Behavior

非技术：生物体中的弹性蛋白为皮肤和肌肉等组织提供出色的机械性能，并且通常存在于提供机械加固的异质结构中。材料工程方法能够生产具有明确结构的弹性体材料，因此在保护材料、药物输送和再生医学等应用领域具有巨大的潜力。pi生产此类材料的方法使用弹性蛋白，这是一种具有最佳弹性性能的昆虫蛋白；树脂可以发生很大程度的变形，完全恢复原来的形状。pi将使用具有特定机械和生物功能的类树脂蛋白，并制造包含这些蛋白和常用合成聚合物的材料。光引发化学的简单处理方案将用于生成不同成分和可预测结构的混合材料。新的表征方法将用于表征单个域的机械性能，并确定这类软材料的结构-功能关系。这个项目的研究不仅有可能影响能源和医学方面的社会需求，也有可能影响不同年龄和经验的学生的教育活动。pi将参与一系列研讨会和学生发起的活动，这将有助于将该计划的概念转化为生物材料技术。技术：在水凝胶中产生3D非均质性的许多方法中，聚合物基微粒复合材料的使用引起了人们的极大兴趣，因为它有很多机会来设计颗粒尺寸、表面积和化学性质。因此，开发简单的一步法生成微结构蛋白质-聚合物基质将为制备非均相材料提供重要的优势，以供系统研究。我们建议利用高弹性多肽弹性蛋白（RLP）溶液的良好相分离，形成微观结构的水凝胶。rlp表现出优异的弹性体和物理化学性质，这将促进所得材料的实用性，特别是在开发模型以了解软水凝胶中的能量耗散方面。pi将功能化RLP，使它们能够进行光引发交联，并将绘制RLP和合成聚合物溶液的相分离图。这些基本信息将允许pi确定适当的组合物和处理条件，将溶液光交联成具有确定组合物和机械性能域的微结构水凝胶。rlp的两种不同的化学修饰将允许pi探测区域的局部力学特性以及区域对水凝胶变形的影响。水凝胶的微观结构将通过显微镜方法进行表征，而力学性能将通过原子力显微镜、空化流变学、小应变接触力学、钝刺力学和体振荡流变学进行表征。鉴于目标应用的丰富和水凝胶材料的广泛使用，拟议的研究将在长期内推进微结构弹性水凝胶在储能、防护装备、药物输送和再生医学等应用中的使用。pi将通过为中学到研究生举办一系列讲习班和活动，促进这些概念转化为技术应用。

ABSTRACT Non-technical: Elastomeric proteins in living organisms provide outstanding mechanical properties to tissues such as skin and muscle, and generally exist in heterogeneous structures that provide mechanical reinforcement. Materials engineering approaches that enable the production of elastomeric materials with defined structures would thus have enormous potential in applications ranging from protective materials, drug delivery, and regenerative medicine. PIs approaches for producing such materials employ resilin, an insect protein that has among the best elastomeric properties reported; resilins are able to deform to a large extent and completely recover their original shape. PIs will use resilin-like proteins that are designed with specific mechanical and biological function and make materials that comprise these proteins and commonly employed synthetic polymers. Simple processing protocols with light-initiated chemistries will be used to generate hybrid materials of different compositions and predictable structures. Novel characterization methods will be used to characterize the mechanical properties of individual domains and determine structure-function relationships in this class of soft materials. The research in this program has the potential to not only impact societal needs in energy and medicine, but also educational activities for students of a variety of ages and experience. A series of workshops and student-initiated activities, in which the PIs will participate, will help transfer concepts of this program into biomaterials technologies. Technical: Of many approaches to generate 3D heterogeneity in hydrogels, the use of polymer-based microparticle composites has been of significant interest, given the many opportunities to engineer particle size, surface area, and chemistry. The development of simple, one-step methods to generate microstructured protein-polymer matrices would thus offer significant advantages for making heterogeneous materials for systematic study. We propose to exploit the well behaved phase separation of solutions of the highly elastomeric polypeptide resilin (RLP), to form microstructured hydrogels. The RLPs exhibit outstanding elastomeric and physicochemical properties that will advance the utility of the resulting materials, particularly in the development of models to understand energy dissipation in soft hydrogels. The PIs will functionalize RLPs so that they are competent for photo-initiated crosslinking, and will map the phase separation of RLP and solutions of synthetic polymers. This fundamental information will allow PIs to identify appropriate compositions and processing conditions for photocrosslinking the solutions into microstructured hydrogels that have domains of defined compositions and mechanical properties. Two distinct chemical modifications of the RLPs will allow PIs to probe the local mechanical properties of the domains and the impact of the domains on hydrogel deformation. The microstructure of the hydrogels will be characterized via microscopy methods, while the mechanical properties will be characterized via a suite of atomic force microscopy, cavitation rheology, small-strain contact mechanics, blunt puncture mechanics, and bulk oscillatory rheology. Given the wealth of target applications and the widespread use of hydrogel materials, proposed studies will in the long term advance the use of microstructured elastomeric hydrogels in applications such as energy storage, protective gear, drug delivery, and regenerative medicine. PIs will facilitate the transfer of these concepts into technological applications by hosting a series of workshops and activities for students from the secondary to postgraduate levels.